Gliederung

Background: Patients with anorexia nervosa (AN) have been recently described to not discriminate between reward and punishment at a neural level and to recruit aberrant neural resources when confronted with rewarding food stimuli [1], [2]. However, these data are concerned with the consumptive phase of reward processing. In the present study we focus on reward anticipation in patients with AN.

Material/Methods: Functional MRI was performed to measure mesocorticolimbic activity to stimuli predicting varying degrees of monetary reward, together with behavioral assessment of subsequent motivation to obtain the respective reward on a trial-by-trial basis. The ongoing study includes patients with acute AN (acAN), weight-recovered AN (recAN) and healthy female controls.

Results: Our preliminary data suggest increased reactivity of the mesocorticolimbic system to stimuli predicting relatively low monetary rewards in both groups of AN patients when compared to healthy controls. AN patients subsequently also spent more effort to obtain low monetary reward whereas there are no differences at higher reward levels. This pattern of results was moderated by temperament; the higher patients scored on the persistence subscale of the TCI the less they differentiated between low and high monetary rewards.

Discussion: AN patients show an inflexible pattern of reward anticipation which is characterized by an equally high sensitivity towards low and high secondary and not disorder-related reward-predicting cues. This insensitivity to incentive salience was moderated by temperament and has been previously described as a central mechanism of drug addiction [3].